TH1

TH1 may refer to:
 * Th1 cell, a type of T helper cells
 * Tianhe-I (TH-1), a Chinese super computer
 * TH1 the scripting language for web pages in fossil (software), the Fossil SCM
 * Windows 10 Threshold 1
 * TH-1, a character in The Source (Ayreon album)
 * TH-1 (Phytophthora infestans), a subpopulation of the Ia mtDNA haplotype of the A2 mating type